Compass



-O XP l 0 N INVENTOR ATTO R NEY Arthur F. R. Corron COMPASS A. F. R.COTTON Filed sept. 15,

Oct'. 7, 1952 Patented Oct. 7, 1952 Armure. R. Cotton, Merrick, my.

Application september" v15, 1947, serial No. 774,130

j In Great Britain September 17, 1946 This invention relates tocompasses.;v The principal object of this inventionis the provision ofan instrument which may beused as a compass, a pair of dividers, or 'asa measu'ring rule. It may also be used as a straightedge and a T square.With modications'it may be used as a protractor or as a beam compass. .fThis instrument may be used by engineers, architects and draftsmen, andit may also be use'dby tool'y makers in the making of tool's'eand dies.lThe instrument herein provided must accordingly be precise and accuratein every respect, and it is accordingly fitted with a'vernier so thatmicrometric measurements `andv adjustments may: be

provided for. v f l Preferred embodiments of this invention-are shown inthe accompanying drawing in which- Fig. 1 is a plan view'of thejfirstembodiment; Fig. 2 is a longitudinal sectionon `the line 2--2 i of Fig.1;

' Fig. 3'is another plan view-of the device shown in Fig. l, showing howit isiused to describeuan arc of a measured radius; 1 I Fig. 4`is afragmentary plan. view` of a second embodiment of this invention; i

Fig. 5A is a fragmentary plan viewof a third embodiment of thisinvention; `and Fig. 6 is a-longitudinal section on the line 8- ofFig.5.I

Referring now to the first three gures ofthe drawing, it will be seenthat the embodiment of this invention therein shown comprises essen.

tially four main parts: a calibrated',;perforated disc I0; la calibratedand perforated vstraightedge II; a fastening member I3'by whichthe discand the straightedge may be piVotally-connected to each other and a pinI4. vA recess is formed in the bottom of the straightedge to accommodatedisc I0, the depth of said recess corresponding substantially to thethickness of said disc so that the bottom surfaces of the disc and `ofthe main body of the straightedge will occupy a substantially commonplane. See Fig. 2. One additional'elementis needed for use of thisdevice as a compass or as a pair Vof dividers, 'and that is la markingmember such as a penciLpen or scriber which, of course, are not shown inthe drawing. 'I

The disc I0 is provided with a centrally located hole through which thefastening member I3 extends. Arranged spirally of .said hole'isaplurality of perforations or holes I2' which are one longitudinallyextending series of holes-'I5 which are spaced from each other'inaccordance with calibrations or graduations I'I. In the drawing twoseries lof holes are shown and-two com- `pletesets of calibrationsaccompany said series of holes,'o`ne set foreach series. Forreasons'which'will hereinafter appear, each series of vholes is lformed in v'alongitudinally extending vgroove I9 which is formed in the body of thestraightedge II.

to register with the disc holesv I2xwhen the disc and the straightedgeare pivotally connected 'to 'v each other as shown-in the drawing.

For convenience in carrying the pin. I4 aroundf,A

and to make certain'that it will not become:

separated from the other members of the device and consequently lost,the pin is provided with a threaded portion which meshes with acorrespondingly tapped'portion of the fastening member :13.

ing member as shown in Figs. 1 and 2.

When the device is used `as a compass, and anfarc of al predeterminedradius is sought to be described, the pin I4 is 'removed from thefastening member I3 and inserted through one ofy the slots I8 andthrough a selected registering `disc hole I2. The pencil, pen or scriberis then vinserted into one of the'holes I5 in the straightedge and withthe pin usedr as a fulcrum or pivotal point, the pencilypenfor scriber,as the case may be, is moved -along an arcular line to .describe the arc25 shown. in Fig. 3.. This arcmay, o course, be continued to complete acircle.v

The function which grooves vI9 perform may now'become apparent. Thestraightedge I I is of fair thickness to lend it j all necessarystrength. The holes I5 :are relatively minute'. Hence,"were it not forgrooves I9 which reduce the thickness of the straightedge at holes I 5,itwould be necessary to provide a pencil or `pen point of exceedinglyfine dimensions'to extend through the holes -and make the necessaryimpressions v'or markings yupon the Apaper runderneath. The grooves arealso used to facilitate selection of'a given hole I5. 'The -writing ormarking instrument is simply run up or down the groove untilltheselected hole is reached, fand it is then-inserted into said hole. y

The mechanical operation yof `the-.device has' above been given. It isimportant to -state 'the theoretical'or mathematical basis `of themechanical operation. Reference to Fig.1 will dis- In lineA withl saidlgrooves and said se- Y ries lof holes l5 are slots IBOrmedin'straightedge II atA aipoint Whichfenables saidslots I8AWh'en'the device is not in use, y l therefore, the pin may be screwedinto the fastenvided oi into ten equal parts. On the rst mentioned sidefractional measurements in terms of eighths of an inch may be had; onthe other side of the straightedge decimal measurements ormeasuhlentsin-terms of tenths f'ianinch'.'

may be liadsr/Thearstside may accordingly begjlo used forfractional workand the second side for work on the decimal scale. y The disc holes l2are divided into two series;.

one of which relates to the rst mentioned side` of the straightedge; andthe second.`;series;z: :of155.

course, relates to the second .side .of thestraightedge.

that the difference between the radial distance of one end of saidspiralrom the center of the disc, fand; the :distanceoff/ the.oilcerenxiv ofs'thef.` spi-ral.ifromo` theecenterf-- of?. thee dise,corresponds:vv toathespa'cing betweennadjacent. holessl Sion the.rstfmentioned sident .the straightedge. Bia-the;V

samectoken; thezdistarice ebetvveen iadj assent.heisstA :1

I Egonfthe @secondfside off, thefrstraiglitedgencorreev spendsstos.thefdfilerencL betweentheeradial;disetanceszm triestino;endsofntheesecond; sygiiralscn.` disci?! Di'fromithei cien-tere, of.saielsdisea` Although:

y rnentidnellassbeenomadeiof two: ser-.called spirals F301:

unzip-dis'erIlLnit{.vviikrheY ppreciatedthaft'. what viis meant-:iszasspiratineffonwhich: theerst'- and secrondisets'infiholesl Zrarefdisposed; thef-rstsetfref latinfgetozthearstisideb the straightedgen,andiY the ,-.v

second'l set relatin'afztog the secondxsidef; ofi. sa'idi. 35A fst'raiiglrtedges:A .1.. f. f

flromctheiforegoing tswdil in. pparennthat the; calibrated perorationsomidisoal I! serve assaave to;.w.ithirr='smallfrantio'nssofiarrie'htlrmr razftenitlri of-fan inchcEach eighthor-...tenthiof ansinclrmayg beibr'okeirupnjnttfasemanyeqnahpartsassthereci are holes I2iniitireetwozzspina'l:sections:orridisel0e nectingxfthie Ifhofles; I2:to:xforrmzascontinuouscslot1 3 I-;suclr.asf. isfsholvmzinzdisc Sroiithe.secondifem-f.- bodime'ntfoffthissinventimin Fi L. calibrations#orjfgradnations `.i32i'determinesthe finenesssofo t1:1e-.

corresponding: to Vtheeiirstsseriese015 hbleszlrisv brokentuplbyfmeanssofigradnationsrSZFntEXxeight s parts; thenlitiseclearithaztfannadj ustment. true-tofl/itlraofeancincntinayibefhado -Ifthe second sec-su tion .ntf spiral1311"." corresponding-:toi th'e: secondi: 55-

series of holesd 2; issdi'vided up intotenequal parts:lby:.meansnfzcalibrations 2 ,z .therr the. fseeondfsid'e of fthestraightedfgezmeybe.fused:for :describing:-

^ circlesiac'curate:toiwithigi 1i/100thy sofc'axr-inchc Inallsothe'r.respectsa'theedevicefas:shbwnfinfFig, 0,

ll.tcor-res'pjo'nds to-.rthef device shovvri f..inf.y the first;

three-.Insignesfoitheidrawinsc A'Ihec-.spiralj` 31.*; hassbeen 1"described-'.1 asv-covering f tWouaidioini-ng'zsectionsircorresppndngfdothe two.'

seriessof holes.122zorrgdisc-vlils. Actually.` theseetvvoficsisectionsmaybe madetoicoincidecwithi.each-tothen: sothatthegenti'iie-:Sinalislobimaybe used forzada jus'tmentsiinzsixtyefourths.-aszwell'rasfhundiiedthseA of :aminch-. Mln-.such caseronlyonefxsidee'ofrthec straightedge'; need be .-used.jirriplacerofifthieftwoo 705 sides above referred to. Using this arrangementit wouldzbevfoundJdesinable-rto: space'fthecliolesron the straightedgeoxieiinchor .025 inchzapartf.;

1n- ;Eigse amiewmakeenuserof smttediiw The devices hereinabove?deserbedvimav1 adi 'l Consideringthe spiralon whihztlie iirstiV seriesof holes I2 is disposed, it Will'be understood' and calibrated cross-bar40 in place of the pivotally mounted discs IU and above referred to. Inthis third form of the invention the straightedge 34 is provided with a,recess 3I which extends transversely thereof at right angles thereto.This recess is adapted to accommodate the crossbar 4I) for slidablemovement of said crossbar relative to said straightedge on a linetransversely of; andnerpendicul'ar toQ'said-'strai'ltedgi Pins 38ihavingrelativelyA largeelieadsearefaix'ed to the straightedge to engage,guide, and prevent accidental displacement ofthe crossbar relative totherstraightedge. The straightedge shown in Figs. 5 and 6 is providedwith a Vsmall extension 35 wli-'iohf-is-Lnot ln'eeded on thestraightedge I I shown injherstlfoungures of the drawing. This ex-'tensiomszprovided'with a bushing 36 corresponding to the fasteningmember I3 above de- 'scrib'ed; This bushing is also adapted toaccommodate the threaded portion of pin I4 so that when thepinziszznotlI-.l use:itgllayfbeiserewedzinto thelrgbuslringi; 35:r:T-his. bush-ingg,mayybeg-used; to taliezzthe-plaice orio-ne offltheepins38aand igivena.. headntozperforindhefsame. functionsas aiopins '.381relattveitoothe crossbarisilb1 `v .v j -I Y.

Corresponding;tonspirafl slcty3 I iii-:disc -30 fisa. diagonallyg'exteny gg -slot.!I. in. Vcrossbari litt.l Th'ereare ecalibra-ti'onseorggraduations; .412,1 on-,1,he.A crossbar. dividing u-pjthesletinto. apredetermined ,I numberfof equal zsections and? ity will them-nder,-stoodf'thatithese ca-lfilmrationssand.their functie-nf. correspondrto@the;calibratiensi3It;ofgdisci.:i A.-

ser'iesfof holes .fl-5 -isforined initheastraightedgefa..

longitudinallmthereof .and-yin aiegroove? corresponds l ing to groovesI9vof the first embodiment; Aa.

singleslotrsisformedrin thes-traightedseigor respondinggtocthenslotsplSeirrstraightedgefl I andf-.

it wilbecseen .that .fregistrationristprovidedgbee tween said .sloti43andnslotalll fof-fthefbrossbar; It will also be seen that the distancebetween"fad-'.-J jacentholes'rl 5 rinstrai-g-htedgef Sfconresriondsftotherdistancesseparatingf` az painter-,imaginary Vlines;Y parallel to thelong sides ointhe'zcrossbar;andsfine-r tersecting: theff oppositeendsvof' slot 4 brin .said crossbar. Thus shouldrthe-zdiagonai,slotfMmedi-w vidediby calibrationsf Evvintozonerhlundred:equal parts, the neteiiectfwouldvbe :to justinent iaecurateftorathundredth of'itheistanceseparating adjacent holes I5 in straightedge..-3iICf.`

If; therefore? ther holesfiorr thez'straigfhted-gei arespacedslotiriotzanaincht aparte-the: compass might befusedforganiiustmentsfftoowthin .loogtirfof am:

inchti. device-:may be: used. inasubstantiall embodiment; these .ftwoeembodiments imambe .n modied; as desired,d.b5@fformingq.ai@singleeseress of.; holesrfl andi-.aa single groovesinethe rst= emebodimenirzand :twoi:seriesforholesiandi grooves;` int.;the third embodiment... This@` issimplyy a matter of choice, and it isdetermined .byjtheey useatofiwhichnthe fdviceeincxquestion: to, .be .fput.

Althoughr thenrstiseriesaofzholesslhas: been .dee^- scribedziasibeing'graduated toaeighths of'jiariiinch4 andthe-second seriesto-.tenths:oian'rinch,;itfwilt; baappreciatedfatliat :this :hasbeenfdonezsimplygfbyy Way of illustration and notibyiwaygof :limitationLprfovidefan ad@4 vantageously be made of transparent plastic material.It may be found desirable, however, for use in engineering workshops tomake this Vdevice of a stronger material such as stainless steel ortempered steel. When plastic is used, a strengthening or reinforcingmember of metal may be employed. In such casey it would be possible toreduce the thickness of the material of the straightedge immediatelysurrounding the holes l5. It would then be possible to use a writing ormarking construction having a finely reduced point of somewhat shorterdimensions than would be possible in the use of a straightedge which isthicker around the holes I5. These holes l5 may also be enlarged abovethe bottom surface of the straightedge to accommodate the body of thewriting or marking implement as distinguished from its writing ormarking point, as the case may be. The enlarged portion of holes l5would then serve as a socket to accommodate `the body of the writing ormarking implement.

place of a pin, penor pencil. It is desirable,

whether the device is made of plastic material or metal or any othersuitable material, to make certain that the material is vsuflicientlyyielding v and resilient to enable the straightedge to conform to thecontours of curved surfaces'.

The device may be modified inA other respects than above indicatedwithout departing from the basic principles of the invention. Forexample, the pins 38 which are used to lock the crossbar 4D in place,may be eliminated and other means which would occur to men skilled inthe art might be used to provide a track for the crossbar 40. The bar isshown in the drawing to be completely removable from the recess 31 inthe straightedge 34. It will be found a simpler matter to carry thedevice from place to place by removing the crossbar from thestraightedge and placing them side by side or superimposed in a simplecarrying case. Although a recess has been shown in the straightedge,this, too, might be dispensed with in other constructions which wouldenable the crossbar to move transversely ofthe straightedge and at rightangles thereto. Use may be made of a tension member, for example, tolock the crossbar in place on the straightedge.- As a substitute for atension member, a clamp screw or a cam member may be used to equaladvantage.

These members, however, are not shown in the drawing, because they areconventionally used for the purpose indicated. Furthermore, it should beremembered that when a pin or scriber through the registering slot andhole in the rst.

embodiment, relative movement between the crossbar and the straightedgeor the disc and the straightedge is prevented. Still another respect inwhich the device may be modified is by substituting holes in thecrossbar for the slot 4I,

these holes corresponding to holes I2 of the iirst embodiment. Othermodications and variations will occur to those skilled in the art andneed not here be listed.

I claim:

A compass comprising a substantially discshaped member having aplurality of calibrated holes formed therein in spiral relation to itscenter point, a straightedge having a plurality of calibrated holesformed therein, longitudinally thereof and in alignment with each other,a slot formed at one end of the straightedge in alignment with thecalibrated holes in said straightedge, said straightedge having a recessformed in the bottom thereof to accommodate the discshaped member,the'depth of said recess correspending substantially tothe thickness ofsaid disc-shaped member so that the bottom surfaces of said disc-shapedmember and of the main body of the straightedge will occupy a commonplane, and a rivet pivotally securing said recessed end of thestraightedge to the top center of said discshaped member, therebyproviding for relative pivotal movement between said disc-shaped memberand said straightedge on a substantiallycommon plane and therebyenabling said spirally arranged holes to enter into registration withsaid slot at different points along said slot, depending upon which holeis in registration therewith.

ARTHUR F. R. COTTON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Y Date 452,054 Sperry May 12, 1891824,299 Huey June 26, 1906 1,154,673 Van Ness Sept. 28, 1915 1,341,457Costovici May 25, 1920 2,342,476 McEvoy et al. Feb. 22, 1944 2,370,741McDonnell Mar. 6, 1945 FOREIGN PATENTS Number Country Date y f 324,597Germany Sept. 1, 1920

